The average number of hours worked per week for married men in the early 1990s had a mean of 42.6 and a standard deviation of 12.9.
a. If two married men are chosen at random, what should be the mean and standard deviation of the total hours worked by the two of them in a week?
b. If two married men are co-workers, each of whose hours worked per week has a mean of 42.6 and a standard deviation of 12.9, which of these can we compute: mean of the total hours worked by both of them in a week, or standard deviation of the total hours worked by both of them in a week, or both of these, or neither of these? Explain.